查看“入门：入门程序”的源代码

[[category:Mybatis]]

== 需求 ==
# 根据用户id查询一个用户信息
# 根据用户名称模糊查询用户信息列表
# 添加用户
# 更新用户
# 删除用户

== 创建工程 ==

== 依赖包 ==
包括：mybatis核心包、依赖包、数据驱动包<br/>
[[File:Mybatis依赖包.png|300px]]

== log4j.properties ==
在classpath下创建'''log4j.properties'''：
* mybatis默认使用log4j作为输出日志信息
<syntaxhighlight lang="xml">
# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
</syntaxhighlight>

== SqlMapConfig.xml ==
在classpath下创建'''SqlMapConfig.xml'''：
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<!-- 和spring整合后 environments配置将废除-->
	<environments default="development">
		<environment id="development">
			<!-- 使用jdbc事务管理-->
			<transactionManager type="JDBC" />
			<!-- 数据库连接池-->
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
				<property name="username" value="root" />
				<property name="password" value="mysql" />
			</dataSource>
		</environment>
	</environments>
</configuration>
</syntaxhighlight>

== po类 ==
Po类作为mybatis进行sql映射使用，po类通常与数据库表对应。<br/>
User.java：
<syntaxhighlight lang="java">
import java.util.Date;

public class User {
	
	//属性名和数据库表的字段对应
	private int id;
	private String username;// 用户姓名
	private String sex;// 性别
	private Date birthday;// 生日
	private String address;// 地址
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", sex=" + sex
				+ ", birthday=" + birthday + ", address=" + address + "]";
	}
}
</syntaxhighlight>

== 程序编写 ==
=== 查询 ===
==== 映射文件 ==== 
在classpath下的sqlmap目录下创建sql映射文件'''Users.xml''':
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="test">
	<!-- 根据id获取用户信息 -->
	<select id="findUserById" parameterType="int" resultType="cn.itcast.mybatis.po.User">
		select * from user where id = #{id}
	</select>
	
	<!-- 自定义条件查询用户列表 -->
	<select id="findUserByUsername" parameterType="java.lang.String" resultType="cn.itcast.mybatis.po.User">
	   select * from user where username like '%${value}%' 
	</select>
</mapper>
</syntaxhighlight>

==== 加载映射文件 ====
mybatis框架需要加载映射文件（在'''SqlMapConfig.xml'''中添加Users.xml），如下：
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	
	...

	<mappers>
		<mapper resource="sqlmap/User.xml"/>
	</mappers>
</configuration>
</syntaxhighlight>

==== 测试程序 ====
<syntaxhighlight lang="java">
public class Mybatis_first {
	
	//会话工厂
	private SqlSessionFactory sqlSessionFactory;

	@Before
	public void createSqlSessionFactory() throws IOException {
		// mybatis配置文件
		String resource = "SqlMapConfig.xml";
		// 得到配置文件流
		InputStream inputStream = Resources.getResourceAsStream(resource);

		// 使用SqlSessionFactoryBuilder从xml配置文件中创建SqlSessionFactory
		sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
	}

	// 根据 id查询用户信息
	@Test
	public void testFindUserById() {
		// 数据库会话实例
		SqlSession sqlSession = null;
		try {
			// 创建数据库会话实例sqlSession
			sqlSession = sqlSessionFactory.openSession();
			// 查询单个记录，根据用户id查询用户信息
			User user = sqlSession.selectOne("test.findUserById", 10);
			// 输出用户信息
			System.out.println(user);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (sqlSession != null) {
				sqlSession.close();
			}
		}
	}

	// 根据用户名称模糊查询用户信息
	@Test
	public void testFindUserByUsername() {
		// 数据库会话实例
		SqlSession sqlSession = null;
		try {
			// 创建数据库会话实例sqlSession
			sqlSession = sqlSessionFactory.openSession();
			// 查询单个记录，根据用户id查询用户信息
			List<User> list = sqlSession.selectList("test.findUserByUsername", "张");
			System.out.println(list.size());
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (sqlSession != null) {
				sqlSession.close();
			}
		}
	}
}
</syntaxhighlight>

=== 添加 ===
==== 映射文件 ==== 
在'''Users.xml'''中添加:
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="test">
	
	...

	<!-- 添加用户 -->
	<insert id="insertUser" parameterType="cn.itcast.mybatis.po.User">
		<!-- selectKey将主键返回，需要再返回 -->
		<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
			select LAST_INSERT_ID() 
		</selectKey>
		insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
	</insert>
</mapper>
</syntaxhighlight>

==== 测试程序 ====
在'''Mybatis_first.java'''中添加:
<syntaxhighlight lang="java">
public class Mybatis_first {

	...

	// 添加用户信息
	@Test
	public void testInsert() {
		// 数据库会话实例
		SqlSession sqlSession = null;
		try {
			// 创建数据库会话实例sqlSession
			sqlSession = sqlSessionFactory.openSession();
			// 添加用户信息
			User user = new User();
			user.setUsername("张小明");
			user.setAddress("河南郑州");
			user.setSex("1");
			user.setPrice(1999.9f);
			sqlSession.insert("test.insertUser", user);
			//提交事务
			sqlSession.commit();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (sqlSession != null) {
				sqlSession.close();
			}
		}
	}
}
</syntaxhighlight>

=== 修改 ===
=== 删除 ===

== 入门小结 ==